Supposedly you can because you're offering them 10% more than the rest of your employees...
I hate this approach, but for most companies in Europe it's the reality that works in their favor.
- Worth is subjective. I'm sure we've all had conversations about someone where some view the person as great and others view the same person as meh or under performing. Value is also determined based on information, which usually people don't have the same amount of. So very possible the hiring person or committee sees different value in a person than fellow engineers or teammates.
- Value judgement, especially for hiring is also point in time. Could very well be the person as presented during interview is a rockstar, but after landing on the team doesn't perform well for whatever reason.
2. That's how it should be in an ideal world but the reality is different and companies know through years of experience that the current system works better for them rather than the one you'd want.